Ershad was picked up from his Baridhara residence and taken to Combined Military Hospital by a joint force of police, Rapid Action Battalion (RAB) and detectives, a news agency reported.

The former president was detained days after he and many of his party candidates withdrew their nominations for the country's general elections next month. RAB-1 Commander Kismat Hayat claimed that they were taking Ershad to the hospital because he was feeling ill. But a political observer said if Ershad was ill, hospital ambulance could have taken him to hospital, not the law enforcers.

The Jatiya Party was a major partner of the Prime Minister Sheikh Hasina-led ruling Awami League. Ershad's party quit the Awami League-led 14-party alliance on November 6, saying it would contest the general elections set for January 5 independently. Ershad and his party men recently said the party would not contest the polls unless all parties take part in it.

The main opposition Bangladesh Nationalist Party has also refused to take part in the elections, saying it would not join the elections unless a non-party caretaker government conducts the exercise. But rejecting their demands, Prime Minister Hasina has said the elections will be held in line with the Constitution.

Earlier on Thursday, Bangladesh Jamaat-e-Islami leader Abdul Quader Mollah was hanged for war crimes in the first execution for excesses like murders and rapes during the liberation war of Bangladesh. Mollah was executed at 10.01 pm, hours after the country's highest court dismissed his petition to review his death sentence.